Chemical pregancy

So a few weeks ago I got my period a day early and it lasted 5 days like normal. 2 days after my "period" ended I was getting sick and feeling pregnant. My husband convinced me to take a test. I tested 6 times and all were positives but faint. Went a week on cloud 9 like yes finally another baby. We were TTC for only a few months. Went to the Dr and my levels were very low (at a 3) so I felt crushed ! Took a few tests days after and all came back negative! Dr thinks it was a chemical.. Any thoughts ?